The present invention relates to a cut-off mechanism for elongate stock and the like, and in particular to a shear-type cutter with a hook-shaped side elevational configuration.
Various machines are used to form wire parts, including machines that form coil springs or other parts formed from elongate metal stock. An example is heavy duty coil springs for vehicle suspensions and the like, which are made from larger diameter wire or rod for certain applications, with the wire diameter often exceeding one quarter of an inch, and can be as great as five eights an inch in diameter. After forming, the spring is typically cut off from the stock being fed into the forming machine by a cutter die that uses converging cutting edges to xe2x80x9cnip xe2x80x9d cut the wire or rod. Nip cutters utilize opposing xe2x80x9cVxe2x80x9d shaped cutting surfaces that are aligned along the edge of the xe2x80x9cVxe2x80x9d shape. During cut off, the edges are brought together, thereby deforming the stock and severing the spring. A large force is required to nip cut larger diameter stock, and the sudden release of this force when the cutting edges sever the stock causes a severe xe2x80x9cjumpxe2x80x9d or xe2x80x9cjoltxe2x80x9d at the moment of separation. This sudden jarring motion caused by the large forces involved creates vibrations and/or movements which are not only uncomfortable for nearby workers, but also may damage machine parts, leading to short tool life. This jarring action or shock load will also jar the machinery out of alignment, requiring costly downtime, and/or cause excessive wear.
By way of example, U.S. Pat. No. 1,835,589 to Bond discloses a linearly actuated cutter for use with a device for forming coil springs. U.S. Pat. No. 2,809,678 to Silko discloses a pivotally mounted clipper having a straight shearing edge for cutting off the end of a spring after it is formed in a spring coiling machine. U.S. Pat. No. 4,873,854 to Russell et al. discloses a cutting tool having a straight cutting edge that is pivotally mounted for cutting off a coil spring after the forming operation.
Although these cut-off devices will sever a formed coil spring, the large cutting forces generated, particularly with larger diameter stock, create excessive noise, and an undesirable jarring motion or xe2x80x9cjoltxe2x80x9d when shearing the elongate stock.
One aspect of the present invention is to provide a cut-off mechanism for forming metal parts from elongate stock and the like. The cut-off mechanism includes a first jaw having a laterally inclined first cutting surface extending between a sharpened leading cutting edge and a trailing edge. A second jaw has a laterally inclined second cutting surface extending between a sharpened leading cutting edge and a trailing edge. A connector assembly pivotally interconnects the first and second jaws in a side-by-side relationship at a location spaced apart from the first and second cutting surfaces. The connector positions the leading edges of the first and second cutting surfaces in close planar alignment to shear cut stock that is positioned therebetween. The leading edge of the first cutting surface has a hook-shaped side elevational configuration extending arcuately between an outer tip portion thereof and an inner base portion thereof. When the first and second jaws are pivotally converged, stock positioned between the first and second cutting surfaces adjacent the outer tip portion of the leading edge of the first cutting surface is incrementally shear cut through its entire thickness to cleanly sever the same to length with minimal vibration or jolt.
Another aspect of the present invention is to provide in a metal forming machine of the type fabricating elongate stock, an improved cut-off mechanism therefor. The cut-off mechanism includes a first jaw having a laterally inclined first cutting surface extending between a sharpened leading edge and a trailing edge. A first cutting edge has a hook-shaped side elevational configuration extending arcuately between an outer tip portion and an inner base portion thereof. The cut-off mechanism further includes a second jaw having a laterally inclined second cutting surface extending between a sharpened leading edge and a trailing edge. The second jaw is pivotally connected with the first jaw in a side-by-side relationship at a location spaced apart from the first and second cutting surfaces. The leading edges of the first and second cutting surface are in close planar alignment to shear cut stock positioned therebetween. A motor is operably connected with at least one of the first and second jaws and mutually rotates the same such that when the first and second jaws are converged, stock positioned between the first and second cutting surfaces adjacent the outer tip portion of the first cutting edge is incrementally shear cut through its entire thickness to cleanly sever the same to length with minimal jolt.
Another aspect of the present invention is to provide a cut-off mechanism for forming metal parts from elongate stock and the like. The mechanism includes a first jaw having a laterally inclined first cutting surface extending between a sharpened leading edge and a trailing edge. A second jaw has a laterally inclined second cutting surface extending between a sharpened leading edge and a trailing edge. A connector assembly translationally pivotally interconnects the first and second jaws in a side-by-side relationship at a location spaced apart from the first and second cutting surfaces. The connector assembly positions the leading edges of the first and second cutting surfaces in close planar alignment to shear cut stock positioned therebetween. The leading edge of the first cutting surface has a hook-shaped side elevational configuration extending arcuately between an outer tip portion thereof and an inner base portion thereof. When the first and second jaws are converged, stock positioned between the first and second cutting surfaces adjacent the outer tip portion of the first cutting edge is incrementally shear cut through its entire thickness to cleanly sever the same to length with minimal jolt. The principal objects of the present invention are to provide a cut-off mechanism for wire coiling machines and other similar fabrication machinery. The cut-off mechanism includes first and second jaws which are pivotally interconnected. The first jaw has a cutting edge with a hook-shaped side elevational configuration that facilitates shear cutting of large diameter stock.